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Formation of nano-dimensional surface structures of adsorbat in the condensation and epitacial growth processes

Work number - M 40 FILED

Submitted by Sumy State University

Author: Dvornichenko Alina Vasylivna

The aim of the work is to carry out a comprehensive study of the processes of  adsorbate structures formation on the surfaces of thin films in adsorption/desorption processes during condensation from the gas phase and epitaxial growth within the framework of theoretical calculations and by using numerical simulation.

The author, on the basis of theoretical studies and numerical experiments, determined that an increase in the adsorbate interaction energy and the intensity of nonequilibrium reactions leads to a decrease in the average size of adsorbate structures; an increase in the adsorption coefficient results in the transition from the configuration with the structures of the adsorbate to the configuration with the vacancy structures through configuration with the labyrinth structure. It is established that at early stages of the system evolution due to the competition of adsorption and desorption processes, an oscillatory regime of adsorbate islands formation at epitaxial growth is observed, the frequency of temperature oscillations increases with the deposition flux.

The results obtained in the work are in good agreement with the known results of experimental studies of the formation of nano-sized adsorbate structures during condensation and at epitaxial growth of crystals. The presented formalism can be used to describe the formation of surface structures in metals, when variations in the temperature of the growing surface in adsorption/desorption processes and the reorganization of adsorbate structures are insignificant, and for systems, such as semiconductors, for which local changes in surface temperature play a decisive role in processes of structure formation.

The scientific basis for the development of recommendations for applied research on the modification or correction of the technology of growing structured thin films with specified morphology of structures, their average size and thickness.

New mathematical models for studying the growth dynamics of separated nano-sized adsorbate structures during condensation and epitaxial growth by taking into account local changes in surface temperature are proposed.

The procedure of numerical simulation of the formation and growth processes of separated single-layer and multi-layer structures of adsorbate on lattices with square and hexagonal symmetry is realized.

Number of publications on the theme of work: 7 articles (4 in foreign publications). According to the Scopus database, the total number of links to authors' publications, presented in the work, is 40, h-index (of related publications) = 4; according to the Google Scholar database, the total number of links is 40, the h-index (of related publications) = 4.